rescued an emaciated dog and now he is in sever pain the day after and running or playing?

he has gained weight, still has some more to gain. we feed him good dog food and he drinks plenty of water. he seriously winces and cries the day after us taking him for a walk or any running play etc. is there vitamins or anything I can do for him to regain his muscle mass???

It doesn't sound like a muscle mass issue to me, it sounds like bone spurs. Bone spurs appear on joints as calcium deposits that collect after injury. They are incredibly painful and can be seen on an x-ray, if you decide to take him in to a vet for examination (which I strongly suggest). A very common joint supplement/pain killer is Rimadyl, which will need to be prescribed by your vet.Also, while putting weight back onto a dog, it's best to have a vet's advice as to how fast the dog should be gaining weight. You want muscle AND fat, not just one or the other. So take him to the vet in the morning, have him looked out, get a feeding plan/schedule, and some Rimadyl and you should be good to go!

That'll have to be done over time. Can you/have you taken him to the vet to see if they can give you tips-or possibly pain pills for the dog?

listen to Jen . rimadyl is very helpful! I know because I have seven dogs